Relay



Feb. 15, 1938. v W D MACGEORGE 2,108,775

RELAY Filed Oct. 8, 1955 345g A p6 W NVENTGR Patented Feb. 15, 1938UNITED STATES PATENT OFFICE RELAY Sylvania v 'Application october s,1935, Serin No. 44,014

Claims.

This invention relates to' relays, and particularly to differentialrelays'for alternating current circuits. y

Relays as developed in the past arranged to respond to small alternatingcurrents have been possessed of disadvantages in that the return toneutral position has been sought by the use of springs or gravity or thelike, with most unstable results.

It is among the objects of thisinvention; to improve relay constructionsgenerally; to provide a relay for small current conditions with apredetermined neutral setting which is obtained Without the exercise ofany but electrical forces; to provide a differential relay with a coilin series with a source of alternating current to move an armature to aneutral position when another coil in series with the iirst isdeenergized; to provide a relay which is statically and electricallybalanced; to provide a relay arranged to respond to a small alternatingcurrent to control a circuit and arranged to respond to a secondalternating current circuit in phase with the first to actuate the relayto vertical or centered position; and many other objects and advantageswill become more apparent as the description proceeds.

In the accompanying drawing forming part of this description;

Fig. 1 represents a diagrammatic plan of a relay constructed inaccordance with the preferred form thereof;

Fig. 2 represents a similar diagrammatic plan of the preferred form ofrelay in a circuit With a Wheatstone bridge circuit and arranged toactuate the relay in accordance with the unbalancing of the bridge.

While the preferred form of relay will be shown as possessed of twoopposed deviating or diverting coils in addition to the neutralizingcoil, it will be understood that but one need be used, or that two maybe used in series.

As the relay has many points of use, it will first be described as theunit to be incorporated in any desired circuits, and quite independentof a given circuit, in contrast to the combination shown in Fig. 2.

Referring to Fig. 1, any suitable support, as the panel III may beprovided, having a pivot point II, upon which the lever I2 is pivoted,and preferably having on one side of the pivot II the contact elementI3, disposed between the opposed contacts I4 and I5, having connectorsrespectively I6 and il, each forming one contact of independentcircuits, the other contact of each of which is the common lead I8,connected to contact I3 through the lever I2 in such manner as to imposeno strain, torque, or other resistance to movement, of the lever I2. Inthis connection it will be clear that connector or lead I8 might beelectrically connected through the pivot II if desired. It will beunderstood, of course, that connectors I6 and i8 are in one circuit, sayfor instance (and purely illustratively) in a circuit with one iield ofa reversible motor (not shown), While connectors II and I8 are inanother circuit, say the opposite field of such reversible motor.

The lever I2 has operatively associated with it an armature or solenoidcore or bar 20 carried by the preferably insulated and at least:nonmagnetic bracket 2|, usually, but obviously not necessarily, on theopposite side of said pivot II from the contacts I3, I4 and I5. Acentering and polarizing coil.22 is disposed about the armature bar orcore 2U having its ends connected to terminals 23 and 24, for attachmentto a suitable source of electrical energy. Preferably the source isalternating current although direct current can obviously be used toeffect the same centering function as later recited, and the coil andarmature arrangement is such that generation of alternating currentmagnetic flux in the centering coil 22 moves the solenoid core tocentered relation, if the latter is free to move, and also maintains thearmature in centered relation in the coil, with a consequent maintenanceof the contact I3 in equally spaced relation relative to contact Il andcontact I5. .Obviously during existence of this positioned condition ofthe lever and contacts, neither circuit I6 and I8 or IT and I8 isclosed. Obviously energization of coil 22 by alternating currentinstantaneously polarizes the ends 40 and 4I of armature 20, withpolarity which reverses with the alternations of current.

Suitably supported on the panel or the like III, preferably in axialalignment with the solenoid core or armature 20, is a deviating orenergizing coil 25, having at one end a terminal or connector 26, and atthe other end a similar connector 2'I, which may be directly coupled toa suitable source of current to be described, or may lead to anotherauxiliary or amplifying diverting or energizing coil 28, at theoppositeend of the armature or core 20, which is wound oppositely from coil 25,and terminates in connectors or terminals 30 and 39. Coil 2-8 obviouslymight have separate connectors and be in a separate Qilfllit 1mm coil25, and this is contemplated, as

shown in Fig. 1. It is to be understood that it is not necessary alwaysto provide two coils, as a single coil can perform adequately in certainconnections, but two coils in the same circuit amplify the push-pulleffect on the armature. It is preferred that coil 25 (and coil 28 ifprovided) be connected with a suitable current source or independentsources of variable strength, preferably alternating current, Varyingfrom no potential to a plus or minus of small or great strength oramplitude according to demands.

Referring to Fig. 2, the same relay structure as just described relativeto Fig. 1, will be observed, as will the diagrammatic showing of aWheatstone bridge circuit, as the illustrative source of thefluctuations in the operating coil of the relay. Assume one lead I9, ofa power line of alternating current comprised of lines 29 and I9, inwhich line connectors 23 and 24 of the neutralizing or centering coil22, are placed so that a continuous flow of alternating current throughcoil 22 is insured, and, which is of.

great importance also, so that the circuit through coil 22 is exactly inphase with the alternating current selectively energizing the coll 25(and/or 28), as will be described. Lead wire I9 leads to one end of thebridge circuit comprised of arms 33 and 34 on one side, having thetap-off lead 35, and arms 36 and 31 on the other side, and having thetap-off lead 38.

In the preferred form of invention, as shown in Fig. 2, the tap-offleads 35 and 38, are respectively joined with connectors 26 and 30,(with the opposite leads 21 and 39 joined) and the elements or legs 33and 34, and 36 and 31 of the bridge are in balance so that thealternating current impressed by leads I9 and 29 is balanced on eachside of the bridge. It will be clear that at that time alternatingcurrent will be flowing in coil 22 so that the alternating currentmagnetic flux is effective to center the core 20 and thus to maintainthe contact I3 out of engagement with either contact I4 or I5 of thesecondary circuits, as there will be no current whatever impressedbetween bridge tap-off leads 35 and 38, and therefore coils 25 and 28will not be energized.

It may be assumed that the Wheatstone bridge circuit is one in which theresistance in one leg is varied in accordance with variations incondition, which condition is susceptible to change in accordance withcontrolling motion of the reversible motor illustratively mentioned ashaving fields in the secondary circuits controlled by contacts I3, I4and I5. Illustratively the condition might be temperature and thebalanced condition of the bridge might be a desired temperaturecondition.. while temperature fluctuations either way would havecorresponding resistance variations and would therefore cause theimpressing of a positive or negative current condition between tap-offleads 35 and 38 which would therefore impress a positive or negativecurrent flow between leads or connectors 26 and 30 through deviatingcoils 25 and 28.

While the same alternating current flow maintains through theneutralizing or centering coil 22, in which the ends 40 and 4I, of core20, would be alternately polarized in accordance with the phase of thealternating current feeding the coil, it may be'assumed thatinstantaneously, for

purposes of description only, core end 40 will be N While core end 4I,is, 0f course, S,

43 vof S polarity. It will be evident that as' the end of core 2U, at 40is instantaneously N, as is the adjacent end. 42 of coil 25, there willbe mutual repulsion so that core 20 is pushed away from coil 25 aboutpivot II, and relay or secondary circuit contact I3 engages fixedcontact I4 to complete a secondary circuit. This action carr be had, ofcourse, from coil 25 alone.

Obviously, with coils 25 and 28 in series, but

reversed, the instantaneous value or polarity of i end 44 of coil 28adjacent end 4I of core 20 with its instantaneous S polarity, will be N,so as to attract core 20 toward itself, and thus to amplify the urge ofthe relay out of its centered position about pivot II, as will beobvious. As

the instant polarity of core 20 shifts due to alternations of thecurrent in coil 22, the instant polarity of the respective ends of coils25 and 28 will shift in phase so that the resultant urge on core 20 isthe same. of the relay there will be no disturbing vibration, torque, orurge effective on the relay at the time of alternation of polarity ofcore ends 48 and 4I, as'the coils 25 and 28 are in phase therewith. Thecentering and actuating or deviating currents must be in phase whenalternating current is used to secure a good rm non-chattering contact.'I'his is important.

Owing to the balance Assuming that the closing of circuit la-u as justdescribed has effected a change of condition through running such motor(not shown). and that responsive thereto the unbalance of the bridge iscorrected and balance thereof is restored, then the current flowingthrough coils 25 and 28 will stop, and the continuing energization ofcoil 22 will be effective on solenoid core 28 to center same and movingabout pivot II to move contact I3 away from xed contact I4 and to breakthe secondary circuit therethrough, but Without permitting contact I3 totouch opposite contact I5 of the other secondary circuit.

Obviously a change of resistance of the bridge legs so as to cause anegative flow through coils 25 and 28, would instantaneously find end 42of coil 25 of "S polarity when the instantaneous polarity of end 40 ofcore 2U was N", so that core 20 would be attracted toward coil 25, toswing contact I3 against contact I5, to close the secondary circuit thuscontrolled by those contacts. Obviously also, the instantaneous value ofend 44 of coil 28 would be S so as to repulse the S pole of end 4I ofthe core.

While many uses will occur to those skilled in the art, other than asdisclosed, as for instance in any desired situation where coil 25 (and28 if provided) may be subjected to direct current,

while the centering coil 22 is subjected either to alternating currentor direct current, certain uses may be pointed out, as follows:

Situations in which the relay will be available in other circuits inmechanical and electrical assemblies will doubtless occur to thoseskilled in the art, but mention must be made of a selected few of suchuses that have occurred to Ame in the connection and which may be listedas follows:

a. Alternating current or direct current Wheatstone bridge circuits inaccordance with the instant disclosure.

b; Photoelectric bridge in comparison of colors or light intensities inwhich the deviating coils may be energized positively or negatively inaccordance with the departure from a given value of photoelectricdevices (not shown) in their circuits.

c. Approximate time delay relay. In this situation a variable constantanrheostat controls the circuit through one deviating coil while a fixednickel resistor arranged to operate at a high temperature (not shown)controls a flow through the other deviating coil. If the resistances areinitially the same when the current is turned on the relay will bebalanced until the nickel resistor heats up sufilciently so as toincrease the strength of current owing through the second mentioneddeviating coil to close one circuit of the relay. By adjusting thcvariable constantan rheostat the length of time required to close therelay can be varied.

d. Under voltage under current relay. In this application a currentproportionate to the line voltage passes to one deviating coil while acurrent proportionate to the line current passes to the other orsecondary deviating coil. If an excess vof current passes through theline the attraction of the secondary deviating coil will exceed that ofthe primary deviating coil and` the relay will act. AConversely if thevoltage in the line falls below normal the relay will also act.

e. Reverse current relay. A current transformer (not shown) is in serieswith a primary deviating coil, while the secondary deviating coil andthe centering or neutralizing coil are both excited from a potentialtransformer having constant voltage characteristics.

f. Speed 'synchronizen Two detached direct current magnetos (not shown)are respectively coupled in driven relation to the equipment to besynchronized, and produce voltages proportional to the speed of theirdrivers, and which respective voltages are impressed upon the respectiveopposite deviating coils of the relay. When the speeds are identical therelay will hold and be held in its neutral position. Any variation inrelative speed of the respective equipments will r actuate the relay andactuate indicator or control equipment.

q. Polarized alternating current or direct current relay. In this usethe centering coil ,is energized from a source having characteristicssimilar to the actuating source and the relay will operate in accordancewith the polarity of the actuating source.

The absence of mechanical agencies to actuate or return the relay partsIto neutral will be appreciated, as will the fact that the relay thusprovided is susceptible to extremely minute or weak currents to exertits proper relay function.

I claim:

l. A differential relay comprising a deviating coil having an axis, anarmature core, means mounting the armature core for guided movement, thecore disposed adjacent to said coil substantially concentric with theaxis thereof, a polarizing and centering coil relative to which the corehas movement and disposed sc that the core is in its iield, and the coreand centering coil acting together as a solenoid, circuit controllingmeans operatively associated with the armature core.

2. A differential relay comprising a support, a deviating coil mountediixedly on the support, an armature core, means mounting the armaturecore for guided movement relative to the support, the core disposed insuch proximity to said coil as to be within the magnetic field thereof,a centering coil fixed relative to the support in such proximity to thecore as to be witihn the magnetic eld thereof and relative to which thecore has guided movement, the centering coil and core'acting together asa solenoid, circuit controlling means operatively associated with thecore.

3. A difierential relay comprising a support, a lever, means pivotallymounting the lever on the support in static balance, an armature coremounted on the lever for movement therewith, a centering coil mountedxedly on the support in position to loosely embrace the core and toexert a solenoid centering action thereon, a deviating coil iixedlymounted on the support adjacent to the core with its axis substantiallyconcentric with the core and with the core within the magnetic eld ofthe deviating coil, circuit co-ntrolling means operatively associatedwith the lever.

4. A differential relay comprising a support, a lever, means pivotallymounting the lever on the support, an armature core mounted on thelever, a centering coil xed on the support and loosely embracing thecore and forming with the core a solenoid to center the core and` holdthe lever in a predetermined angular position relative to the pivotalmounting, a deviating coil mounted on the support adjacent to one end ofthe core in substantially concentric relation to the core so as to urgethe core out of its centered position in the centering coil whensuitably energized, a second deviating coil Afixedly mounted on thesupport adjacent to the other end of the core in substantiallyconcentric relation to the core so as to urge the core out of itscentered position in the centering coil when suitably energized,electrical connecting means joining the deviating coils in series but inreversed relation so that each augments the urge of the other on thecore.

5. In a relay, an armature having a neutral position and a circuitclosing position, circuit controlling means operatively associated withthe armature, means supporting the armature for guided movement betweenneutral and circuit closing position, a hollow fixed polarizing andcentering coil adjacent to said armature, a core mounted on the armatureand disposed within the coil and in neutral position, a deviating coilfixed relative to the centering coil adjacent to said core whereby itsmagnetic lflux is effective on said core to move the armature to circuitmaking position.-

6. In combination, a source of A. C., a fixed polarizing and centeringcoil continuously in circuit with said source, a fixed deviating coil incircuit with'said source, an armature including a core, said coredisposed within and forming with the centering coil a solenoid, saidcore being disposed within the magnetic field of said deviating coil,means mounting the core for guided movement between its solenoidposition and a modication thereof incident to energization of thedeviating coil, means for energizing the deviating coil with A. C.current of selected polarity instantaneously identical with or exactlyopposite to that flowing inthe centering coil so that their zero pointsoccur at the saine instant, and circuitl controlling means controlled bysaid armature.

7. In combination with a source of alternating current, a relaycomprising an armature core, means mounting the core for limited guidedmovement, a centering coil loosely embracing and lxed relative to saidcore and forming with said core a solenoid, a deviating coil fixedrelative and adjacent to said core and centering coil and having an axissubstantially concentric to said core, means including connectionsbetween said source and said centering coil and deviating coil Awherebythe centering coil is continuously energized with said alternatingcurrent and the deviating coil is arranged for energization withalternating current of selected potential in exact phase with that ofthe centering coil although selectively of the same or oppositedirection whereby lthe deviating coll exerts attraction or repulsion onsaid core, and circuit controlling means operated by said armature core.

8. A differential relay comprising a support, a lever arm, meansmounting the lever arm for pivoted movement relative to said support, acore, a centering coil fixed to the support and loosely embracing saidcore, a yoke having spaced legs engaging the core on opposite sides ofsaid centering coil and mounted on said lever arm to permit limitedsubstantially 'axial movement of the core in the centering coll bymovement of said lever about its pivot, and a deviating coil mounted onthe support adjacent to and substantially concentric with the corebeyond the yoke.

aftosa/7s the core in the centering coil by movement oi said lever aboutits pivot, a pair of deviating coils spaced apart and fixed to thesupport and each substantially concentric with and adjacent to the coreon opposite sides oi the yoke.

i0. A dierential relay comprising a support, a lever arm, means mountingthe lever arm for pivoted movement relative to said support, a core, acentering coil fixed to the support and loosely embraclngsaid core, ayoke having spaced legs engagingthe core on opposite sides of saidcentering coil and mounted on said lever arm to permit limitedsubstantially axial movement of the core in the centering coil bymovement oi said lever about its pivot, a pair of devia-ting coilsspaced apart and xed to the support and each substantially concentricwith and adjacent to the core on opposite sides of the yoke, and connecmtions joining the deviating coils in series in re versed directions sothat with a current iiowing through both coils the instantaneouspolarity of the end o one coil adjacent to one end of the core isopposite to that of the end ci the other coil adjacent to the other endof the core so that the deviating coilsr supplement each other.

vnmmaivi n. Mandaeans..

